Solar cells are devices that convert the energy of light into electricity using the photovoltaic effect. Solar power is an attractive green energy source because it is sustainable and produces only non-polluting by-products. Accordingly, a great deal of research is currently being devoted to developing solar cells with enhanced efficiency while continuously lowering material and manufacturing costs. In operation, when light hits a solar cell, a fraction of the incident light is reelected by the surface and the remainder is transmitted into the solar cell. The photons of the transmitted light are absorbed by the solar cell, which is usually made of a semiconducting material such as silicon. The energy from the absorbed photons excites electrons of the semiconducting material from their atoms, generating electron-hole pairs. These electron-hole pairs are then separated by p-n junctions and collected by conductive electrodes applied on the solar cell surface.
Solar cells typically have electroconductive pastes applied to both their front and back surfaces. A front side paste, which typically includes silver, is screen printed onto the front side of the substrate to serve as a front electrode. A typical electroconductive paste contains conductive metallic particles, glass frit, and an organic vehicle. In some instances, the glass frit etches through an antireflection coating, such as a silicon nitride coating, on the surface of the silicon substrate upon firing, helping to build electrical contact between the conductive particles and the silicon substrate. At the same time, some known glass frits, which help to build electrical contact, also contribute to deteriorated adhesion of the paste to the silicon substrate. As a result, the adhesive performance and reliability of the solar cell may be reduced.
Thus, an IRS which provides improved adhesion between the electroconductive paste and the underlying substrate so as to achieve enhanced solar cell efficiency is desired.